This invention relates, in general to electrophotographic apparatus and more particularly, to contact fixing apparatus therefor.
In electrophotographic reproduction machines, contact heat fixing apparatuses using heating rolls have often been employed as fixing means. The contact heat fixing apparatus of this type comprise, as shown in FIG. 1, a pair of rolls 1 and 2 provided on the surfaces thereof with covers 5 and 8 of non-adhesive material, for example, tetrafluoroethylene resin or silicone rubber, fluorocarbon resin or the like. Either one or both of the rolls 1 and 2 may be axially provided with a heating device 3 such as tubular infrared lamps or the like. The rolls 1 and 2 are rotatably supported for contact with each other and an appropriate pressure is applied therebetween to form a nip through which a support 9 having non-fixed thermoplastic powder 10 (referred to as toner hereinafter) deposited thereon is passed for fixing the non-fixed toner to the support. The contact heat fixing apparatus described above is advantageous in that it can be used with less electric power than fixing apparatus utilizing irradiated heat as well as without dangers of fire hazard and burning.
In conventional reproduction machines, most of the electric power used in the entire machine is consumed by the fixing apparatus and when the total electric power consumed by the machine is determined the number of sheets of copy paper obtainable per unit time are automatically set from the electric power required for the continuous reproduction, even if the above contact heat fixing apparatus requiring relatively less electric power is used.
Reproduction machines which can be used with receptacles or power outlets rated at 100V and 15A are highly desirable where the electric power available for the fixing system is between 700-100W after taking into consideration the electric power required for the driving system, optical system, developing system or the like from the totally available power of 1.5 KVA. At present most of the reproduction machines generally provide 1000 to 2000 sheets of copy paper per hour when using a contact heat fixing apparatus, depending upon the heat efficiency of the fixing apparatus. It has been difficult to provide a reproduction machine capable of satisfying the requirements such as having a reproduction speed of 2500 sheets per hour and rated power consumption less than 1.5 KVA so long as conventional contact heat fixing apparatuses are used.
This invention has been accomplished in view of the foregoing and it is an object of this invention to provide a contact heat fixing apparatus for electrophotographic reproduction machines capable of increasing the reproducing speed within the above described conventional rated power consumption.